Babio beceitek attachment fob telephomes



' 1,622,335 March 29, 1927. G. F. MITCHELL RADIO RECEIVER ATTACHMENT FORTELEPHONES 'F'iled Oct. 5, 1925 s Sheets-Sheet 1 March 29, 1927.1,622,335

G. F. MITCHELL RADIO RECEIVEHATTA CHMENT FOR TELEPHONES Filed 001,.5,1925 3 Sheets-Sheet 2 gwue'ntor 25% d M 6mm? March 29,1927. 1,622,335

G. F. MITCHELL RADIO RECEIVER ATTACHMENT FOR TEL EPHONES.

Filed Oct. 5, 1925 s Sheets-Sheet 5 IIHIIIIIIIIII [w llmllllllii snowMow enonen r. MITCHELL, or wasnrneron, premier on confine.

RADIO RECEIVER ATTACHMENT FOR TELEPHONES.

Application filed October My invention relates broadly to radioreceivlng systems and more particularly to the construction of a radioreceiver which may be attached to the standard telephone.

s Une of the objects of my invention is to provide a simple construction.of radio receiving apparatus which may be readily attached to thestandard house telephone for the reception of radio broadcast news,conto certs, music and entertainment.

Another object of my invention is to provide a construction of radioreceiving apparatus which is readily attachable to a standard tele honeand which may be readily conl nected 1n the telephone circuit withoutthe necessity of erecting an antenna or modifying the telephoneinstallation in any way heyond making simple connections with thetelephone conductors. 2i? Still another object of my'invention'is toprovide a practical construction of rio receiver attachment fortelephones which may be readily transported from place to lace andsecured to the telephone ready 95 or operation without interference withthe normal functioning of the telephone. A further object of myinvention is to provide a radio receiving attachment tor telephoneswhich may he snapped upon the usual telephone stand and t e usualtelephone receiver utilized both for the recep-" tion of radio signalsin addition to its usual .icunction as a receiver for the line wiretelephone communication.

Other and further objects of my invention will be understood from thespecification hereinafter following by reference to the accompanyingdrawings, wherein Figure 1 is a side elevation showing the radioreceiver attachment secured to a telephone stand; Fig. 2 is a rear viewshowing.

usual telephone receiver is employed "for the reception of radiosignals; Fig. 6 is a modified view of a radio receiver attachmentemploying an adjustable tuning inductance; r Fig. 7 is a perspectiveview showing a telephone stand with the radio receiver attachment of myinvention secured thereto; Fig. 8

3, 1925. Serial No. 60,345.

\ apparatus of the radio receiver attachment.

Referring to the drawingsin more detail, retesence character 1represents the telephone stand which includes the carrier hook 2 forsupporting the telephone receiver 3. A flexible connection 4 is providedbetween the telephone receiver 3 and the telephone stand 1 from whichthe conductor 5 leads to the telephone box and line. The telephone standcarries the transmitter 6. A 1

vertical longitudinally extending supporting member 7 is providedforming the housing for the radio receiving apparatus with an insulatedplate 8 forming one side thereof, The supporting member 7 conformssubstantially to the shape of the telephone stand 1 and base top portion9 at the upper extremity thereof which supports a rectifier or crystaldetector. The supporting member? is detachably secured to the telephonestand 1 by means of the resilient devices 10 and 11 having spring arms10 and 10", and 11 and 11", which grip opposite sides of the telephonestand. A contact strip 12 is provided at the upper extremity of thesupporting member 7 which engages and establisheselectrical connectionwith a portion'ot the telephone stand 1. The rectifier comprises a cupmember 14 which contains sensitive crystal 15. A standard 16 is mountedon the plate 9 permitting an arm carrying a cat whisker 17 to be movedto various positions by means of universal joint 19 under control of theadjusting knob 18. I provide a latch 20 pivoted at one side of thesupporting member 7 and arranged to overlie the hook 2 in abutment withpin 21 for preventing the operation of the hook 2 when the telephonereceiver 3 is used as the radio receiver and is removed from the hook'2. In Fig. 10 I have illustrated a. simplified arrangement of thereceiving circuit wherethe telephone headset 22 is connected acrossterminals AA' and BB which connect respectively with the contact member22 establishing connection with6 the telephone stand and the ground at 21 of. As represented in Fig. 13 I ma In Fig. 11 I have shown a form ofreceiving apparatus where the telephone headset 22 is shunted by meansof a condenser 23 and wherein a tuning in' uctance 24 with' adjustablecontact 25 is provided as schematically illustrated in Fig. 6. I mayprbvide an electron tubecircuit at the receiver as represented in Fig.12 where a variable tuning condenser 27 is positioned between thecontactmember-12 and the tuning inductance 24 and the tube 28 arranged tofunction as a detector with grid condenser and grid leak 29in the inputcircuit thereprovide stages of amplification after he detector 1517 withan audio frequency coupling transformer 30 arranged to impress therectified energy upon the amplifier tube 31. Fig. 14 illustratesschematically the principle of my radio receiver attachment, where theinput circuit of the radio receiver apparatus is virtually connected toone side of the telephone line 32 through the inherent capacity 33existing between the telephone stand and the leads. A couplingtransformer 34 may be arranged to impress the received signaling energyupon the detector circuit.

In Fig. 5 I have shown .the telephone stand 1 broken away illustratinginterior contacts 35, 36, 37, and 38 interiorly ofthe stand. Wires leadfrom binding posts E and F to the conductors 4 which connect with thetelephone receiver 3. In order to more clearly illustrate my invention Ihave shown the terminals AA and BB in the cross-sectional view of Fig. 5one below the other although it will be understood that they wouldnormally appear one behind the other. Flexible connectors 39 and 40rovided with pin connections are arrange to be passed through theinsulation of the flexible conductor 4 to com lete an electrical circuitthrou h the telep one receiver 3, placing the te ephone receiver 3 inthe out put circuit of the radio receivin apparatus.

Fig. 7 more ,clearly shows the arrangement of parts of the radioreceiver attachment. The wiring arrangement when the telephone receiver3 is used in theoutput circuit of the radio receiver is'illustrated inFig. 15. In Fig. 8 I have shown the supporting member 7 enclosingminiature electron tubes 42 and 44 and coupling transformers 41 and 43for increasing the amplitude of the received signaling energy to such apoint that reception at any desired volume is practical over the radioreceiver attachment. In Fig. 9 Ihave shown a terminal face 49 which is.formed directly upon the telephone stand 1 providing socket terminals 45for cooperation with pin terminals 47 on the connector 46 which connectsthrou h flexible lead 48 with the output cir- .cuit'o the radioreceiving set. In this construction it is unnecessary to provide pin tapconnections between terminals AA and BB when it is desired to utilizethe telephone receiver 3 both asa receiver of radio signals and asareceiver of the normal line wire telephone communication.

It will be understood that the radio receiver attachment o f myinvention may be employed on the usual telephone stand withone side ofthe line is groun ed the radio I set can be connected with the groundedside of the line and an independent ground connection 26 becomesunnecessary.

While I have described my invention in certain particular embodiments Idesire that it be understood that modifications may be made and that Iintend no limitationsupon the invention other than those imposed by thescope of the appended claims.

What I claim and desire to secure-by Let- .ters Patent of the UnitedStates is as follows:

1. A radio receiver attachment for telephones com rising, incombination, a telephone stan a support adapted to carry radio receivingapparatus, a contact member extending rom said support, and spring armscarried by said support for engagement with opposite sides of saidtelephone standfor securing said support with respect to said telephonestand with said contact member in operative engagement with the upper'extremity of said telephone stand for-establlshing electricalconnection therewith.

2. A radio receiver attachment for telephones com using, in combination,a telephone stan a supporting block substantlally conforming to theshape of said telephone stand, said bIock carrying radio receiving.apparatus thereon, and members extending from said block and engagingsaid telephone stand, at least one of said members establishingelectrical connection between said apparatus and said telephone standfor completing an electrical circuit through said receiving apparatus.

3. radio receiver attachment for telephones comprising, in combinationwith a telephone stand, supporting block arranged to carry radioreceiving apparatus, resilient clip members for securing said supportingblock in engagement with ,said telephone stand, and a'contact membercarried by said block for directly contacting with said tele- 7 phonestand torestablishing electrical con-- messes nections between saidradio receiving ap aratus and said telephone stand for comp eting theelectrical circuits through-said radio receiving apparatus.

ivA radio receiver attachment for telephones comprising, in combinationwith a telephone-stand, supporting member adapted to carry radioreceiving apparatus and having terminals for the connection of atelephone headset in circuit therewith, and securing members extendingfrom said S11 porting member for engagement with said telephone stand,one of said securing members establishing electrical connections withsaid telephone stand for completing the electrical circuit through saidradio receiving apparatus.

5. A radio receiver attachment for telephones comprising, in combinationwith a telephone stand, a supporting member carrying radio receivingapparatus, a ground term nal on said supporting member for electricallyconnecting said radio receiving apparatus to ground, mounting memberssecured to said supporting member for engagement with said telephonestand, and a contact member carried by said supportin member for.directly contacting with sai stand for establishing electricalconnection between said radio receiving apparatus and said telephonestand for completing the electrical circuit through said radio receivingapparatus 6. A radio receiver attachment for telephones comprising, incombination with a telephone stand, a supporting member ar ranged tocarry radio receiving apparatus, circuit connections for said radioreceiving apparatus within said supporting member, terminals carried bysaid supporting memher for the connection of a telephone headsaid supsaid radio receiving apparatus, resilient clips set with said radioreceiving apparatus, a and connection terminal carried by saidsupporting member for establishing a circuit from said radio receivingapparatus to ground, resilient means for securing said supporting memberon said telephone stand, and a connecting member carried by saidsupporting member and arranged to directly en age said telephone standand establish electrical connections between said radio receivingapparatus and said telephone stand.

7. A radio receiver attachment for telephones comprising, in combinationwith a telephone stand, a supporting member adapted to carry radioreceiving apparatus,

a crystal detector mounted on said sup orting member, terminal memberscarrie by rting member and connected with for securing said supportingmember tosaid telephone stand, andv a member extending from one side ofsaid crystal detector for engaging said telephone stand and establishingelectrical connections therewith.

8. A radio receiver attachment for telephones comprising, in combinationwith a telephone stand having a telephone receiver and a hook carriertherefor, a supporting member adapted to carry radio receivingapparatus, means for detachably securing said supporting member to saidtelephone stand, terminals carried by said supporting member forestablishing connection between said telephone receiver and said radioreceiving apparatus, and means carried by said supporting member forpreventing operation of the telephone receiver hook carrier when saidtelephone receiver is removed from said hook and connected with the saidradio receiving apparatus.

9. A radio receiver attachment for telephones comprising, in combinationwith a telephone stand including a telephone receiver and a hook carriertherefor, a sup-- porting member, means for detachably securing saidsupporting member to said telephone stand, radio receiving apparatuscarried by said supporting member, a member connected with said radioreceiving apparatus and engaging said telephone stand tor establishingelectrical connection therewith, output terminals for said radioreceiving apparatus carried by said supporting member,

means for establishing connections between said output terminals andsaid telephone receiver and means carried by said supporting member forpreventing operation of said hook carrier when said telephone receiveris removed therefrom and connected with said output terminals.

10. A radio receiver attachment for telephones comprising, incombination with a telephone stand including a telephone receiver and ahook carrier therefor, a supporting member adapted to carry radioreceiving apparatus, resilient means for detachably securing saidsupporting member to said telephone stand, a pair of output terminals, aground terminal and an'antenna terminal carried by said su portingmember, said antenna terminal eing arranged to engage with saidtelephone stand and establish electrical connection: therewith, meansfor establishing connections between said telephone receiver and saidoutput terminals, and means carried by said supporting member forpreventing operation of said hook carrier whensaid telephone receiver isremoved therefrom and connected with said radio receiving apparatus.

11. A radio receiver attachment for tele-l phones comprising, incombination with a telephone stand including a telephonereceiver and ahook carrier therefor, a sup porting member, means for detachablysecuring said supporting member to said telephone stand, radio receivingapparatus car= ried by said supporting member and having outputterminals with leads extendin therefrom for the connection of saidteephone receiver therewith, and a latch member carried by said supportinginember for pre-' venting operation of said hook carrier when saidtelephone receiver is removed therefrom and connected. with said outputterminals.

12. A radio receiver attachment for tele phones comprising thecombination with a telephone stand having a telephone receiver and ahook carrier therefor, of a supporting member adapted to carry radioreceiving apparatus, means for detachably securing said supportingmember tosaid telephone stand, a terminal carried by said member andadapted to be brought into electrical contact with said stand to connectthe radio receiving apparatus with said stand when said member issecured to the stand, output terminals carried by the supporting memberand in connection with the receiving apparatus, and conductors forestablishing connection between the output terminalsvof the apparatusand the telephonereceiver.

13. A radio receiver attachment for telephones comprising thecombination ofa supporting member provided with means for detachablysecuring'said member to a telephone stand, a terminal carried by said,member and adapted to be brought into electrical contact. with saidstand when said member is secured to said stand. and means carried bysaid supporting member for preventing operationof the hook switch ofsaid telephone stand when said member is secured to said stand.

GEORGE F. MITCHELL.

